Low temperature process for making radiopac materials utilizing industrial/agricultural waste as raw material

摘要

A novel process is for making ceramic based radiopac materials useful for X-ray radiation attenuation. The process is lead as well as rare earth free and thus obviates (i) the use of conventionally used lead metal and its compounds—which are toxic in nature and are heavy weight as the density of lead is 11.34 gm/cm-2. Further the low melting points of lead (325° C.) prohibits its use in high temperature shielding structures and (ii) the use of Rare earth is restricted because they are very costly and scarcely available. The novel process of the present invention utilizes different varieties of waste as raw materials such as fly ash (from thermal power plants), Red mud (from aluminum production), Rice husk silica (an agro waste) and pyrophyllite (an underutilized clay mineral). These waste materials contain various necessary constituents required for making radiopac materials namely silicon, titanium, iron and aluminum. The presence of different mineralizers in the raw materials used and use of phosphatic binders significantly helps in obtaining the radiopac materials, at relatively low temperature of 920° C. itself and thus leads to saving of considerable heat energy. Further as the waste are generated in powder form, the use of these waste also helps in saving on the account of grinding energy. The radiopac materials obtained by the novel process of present invention are capable of withstanding ambient to high temperature and thus finds wide applications in making aprons, gloves and ceramic tiles, bricks for attenuation of X-ray radiations. The radiopac materials are useful as materials for construction of partition wall of X-ray room in hospitals, research institutes and industries. Apart from this radiopac materials an also be used and in making high temperature X-ray attenuation structures.